The best way to housebreak (or garage break) any dog is with a crate. Very few dogs will make a mess in their crate if it is the right size. The idea is that their crate is equivalent to a wolf's den. They want to keep their special place clean. If the crate is too large and they can mess in one corner and get away to the opposite corner, they may do that. However, most dogs keep their crates clean. Put your dog in his crate whenever you can't supervise him. As soon as you let him out, take him outdoors to do his business and praise him lavishly as soon as he pees or poops. You can even reward him with treats or a toy if you want. You want him to get the idea that outdoors is where he relieves himself. If you want him to always go to the same place, then always take him there on leash so he cannot chose for himself. Never scold him for making a mistake in the house or the garage unless you catch him in the act. Dogs only make connections between actions and their consequences within a few seconds time. That's why rewards have to come so quickly for good behavior.